Sorry, I should have made it clear, as I did in my initial post about
this - this is a switch for RX antennas only - specifically 160M options.
73, Pete N4ZR
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On 1/1/2012 11:23 AM, Kelly Taylor wrote:
> Hi Pete,
>
> It seems to me: you're attempting to couple both your two-way HF energy and
> the UHF energy required for switching onto a common feedline, is that right?
>
> It seems it would be doable, but the difficulty to me appears to be
> isolating one from the other at both ends of the feedline. You don't want
> your HF energy to fry the switch and I'm pretty sure it would be some kind
> of rules violation to radiate that UHF energy through your antennas.
>
> You probably are looking at some type of duplexer/diplexer arrangement,
> where one port at the shack end accepts HF, the other accepts UHF and at the
> switch end, only UHF comes out of one port and only HF comes out the other.
>
> If you're running power, the question then becomes: is this cheaper than
> just running another length of feedline?
>
> Because both are RF, it seems more difficult to me than injecting DC (a la
> RCS4). Perhaps if you built identical tuned circuits resonant at UHF, these
> could couple/uncouple the UHF energy (appearing as an open circuit to HF)
> and then put a low-pass filter north of the uncoupling circuit? Perhaps you
> also need a low-pass filter south of the coupling circuit, I don't know.
>
> Of course, the feedline is going to be just as lossy at UHF with the couple
> HF/UHF signals as it would with just UHF, so you'd have to know that you're
> getting enough UHF out the other end to work.
>
> 73, kelly
> ve4xt
>
> On 1/1/12 9:18 AM, "Pete Smith"<n4zr@contesting.com> wrote:
>
>> I am planning to build, in the next couple of days, the couplers needed
>> to test this idea. To revisit it, I have qn inexpensive RF-controlled
>> 8-way band switch, and several people suggested that I should couple the
>> RF from the "remote" to my feedline, and pick it off the other end, to
>> eliminate path losses over the ~300 foot range.
>>
>> This seems plausible to me, but as usual I'm having trouble figuring out
>> the specifics. Say I take a piece of RG-59, remove the jacket and the
>> shield braid, and then couple the output from the remote to the center
>> conductor moni-match style. Should I lay the coupling wire parallel to
>> the center conductor, or should I wind it around the insulated center
>> conductor? What sort of total length for the coupling wire would give
>> best results at ~315 MHz? Any difference in the design of the coupler
>> on the receiving end?
>>
>> I assume I should pull the braid back over the "coupler" section - is
>> that right? If I have common mode chokes (#31 toroids) on both ends of
>> the feedline, will it be better to have the couplers between the chokes,
>> or doesn't it matter, since the UHF RF will presumably be going by
>> differential mode?
>
>
>
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